1. Field of the Invention
The present invention relates to a legged locomotion robot provided a tiptoe in a foot serving as a tip end portion of a leg connected to an upper body with improved locomotion performance.
2. Description of the Related Art
Hitherto, there has been known a legged locomotion robot provided with a foot as described below.
According to Japanese Patent Laid-open No. 2003-048178, there has been disclosed a foot provided with a joint portion passively and rotatably connected to a tiptoe portion at a position offset from a ground contacting portion of the foot.
According to Japanese Patent Laid-open No. 2004-090194, there has been disclosed a foot provided with a base portion fixed at a corresponding lower end of a leg, a heel portion fixed around a rear end of the base portion and a pair of tiptoe portions extending in parallel from the base portion to the front substantially and swingably supporting the base portion in the vertical direction.
According to Japanese Patent Laid-open No. 2005-153038, there has been disclosed a foot provided with a foot sole having a ground contacting surface disposed at the lowest end of a locomotive leg, a plurality of tiptoe portions rotatably mounted at a front end edge of the foot sole through a joint shaft disposed in a different direction from a pitch axial direction of a body of the legged locomotion robot.
According to Japanese Patent Laid-open No. 2005-169544, there has been disclosed a foot provided with a first foot sole and a second foot sole connected swingably with each other, and an actuator for swinging the two foot soles relatively, wherein the first foot sole is connected to a crus portion of a walking robot, the second foot sole has a ground contacting portion, a swing shaft between the two foot soles is disposed around a front end of the first foot sole and extends in the lateral direction, and the ground contacting portion of the second foot sole extends over the swing shaft in the anteroposterior direction at the ground contacting state.
However, according to the above-mentioned conventional arts, the foot is provided with a rotatable joint for joining the tiptoe portion to the foot, which makes the structure thereof complicated, leading to a problem of high cost.